Don't accept any blksize

diff --git a/tftp.c b/tftp.c
index f5ad35a75c996c7bf8c6d61e7bd69e614fae9d22..a11023841480dcdff3a5a233dad51847828dd013 100644 (file)
--- a/tftp.c
+++ b/tftp.c
@@ -30,7 +30,7 @@
 #define O_BINARY 0
 #endif
 
-#define TFTP_PKT_SIZE 516
+#define TFTP_BLKSIZE 1456
 
 static const char *opcode_names[] = {
        "RRQ", "WRQ", "DATA", "ACK", "ERR", "OACK"
@@ -374,7 +374,7 @@ int tftp_put(struct nmrpd_args *args)
        /* Not really, but this way the loop sends our WRQ before receiving */
        timeout = 1;
 
-       pkt_mkwrq(tx, file_remote, 1456);
+       pkt_mkwrq(tx, file_remote, TFTP_BLKSIZE);
 
        while (!g_interrupted) {
                ackblock = -1;
@@ -387,7 +387,7 @@ int tftp_put(struct nmrpd_args *args)
                                ackblock = 0;
                                if ((val = pkt_optval(rx, "blksize"))) {
                                        blksize = strtol(val, &end, 10);
-                                       if (!blksize || (*end != '\0')) {
+                                       if (*end != '\0' || blksize < 8 || blksize > TFTP_BLKSIZE) {
                                                fprintf(stderr, "Error: invalid blksize in OACK: %s\n", val);
                                                ret = -1;
                                                goto cleanup;